Comment by Terr_

That's incomplete, because another "nobody remembers" is when the hallucination differs from reality, but the reader doesn't promptly detect the problem and remember where they got it from.

Think about the urban legends in the style of "the average person eats X spiders per year." It's extremely unlikely that Rumor Patient Zero is in a position to realize it's wrong, or that they will inform the next person that it came from an LLM summary.